Removable cement retainer



April 7, 1942. G. GREEN REMOVABLE CEMENT RETAINER Filed Aug 14 1 GEORGE GREEN in a ENTOR.

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Patented Apr. 7, 1942 UNITED STATES PATENT OFFICE REMOVABLE CEMENT RETAINER George Green, Houston, Tex.

Application August 14, 1939, Serial No. 289,973

11 Claims. (Cl. 166-12) The invention relates to a releasable cement retainer to be used in wells during the cementing operation.

In the drilling of wells by the rotary method it is usual either during or after the drilling operation to case the well and to apply cement under pressure adjacent the lower end of the casing so as to force the cement outwardly around the casing and into the formation so as to provide a complete seal. In other instances it is desirable to force cement around a liner or strainer at various elevations and to apply this cement under pressure in what is generally known to the trade as a squeeze job because the cement is squeezed into place. After the cementing operation has been completed it is desirable to remove all of the tools and equipment from the well which have been utilized in the cementing operation and the present invention directs itself to a tool which can be lowered into the well bore and set so as to form a stop in the well to confine the cement when pressure is applied to the cement as it is forced thru the tube and which tool can thereafter be released and removed from the well and which tool may also be opened up so as to prevent circulation thru the well above the packer and thru the tool.

It is one of the objects of the invention to provide a cement retainer which can be anchored by hydraulic pressure.

Another object of the invention is to provide a removable cement retainer which can be set by hydraulic pressure and thereafter opened up to permit circulation thru the operating string and the well above the retainer.

Another object of the invention is to provide a retainer in which pressure is applied to set the retainer in position and which pressure is thereafter released after the setting has been accomplished.

Another object of the invention is to provide a movable plunger so that a packer may be set by hydraulic pressure.

Another object of the invention is to set an anchor by hydraulic pressure and to thereafter effect the setting of a packer by a pull upon an operating string from the surface and to also utilize the efiect of hydraulic pressure exerted on the lower end of the tool to assist in setting the packer.

Other and further objects of the invention will be readily apparent in the following description as considered in connection with the accompanying drawing wherein:

Fig. 1 is a side elevation with certain parts in section of the upper end of the tool, shown in the position in which it will be lowered into the well bore.

Fig. 2 is a view similar to the Fig. 1 showing the lower end of the tool. I

Fig. 3 is a section taken on the line 3--3 of Fig. 1.

Fig. 4 is a side elevation with certainparts in section illustrating the packer as having been set by hydraulic pressure and held in position by tension on the operating pipe.

The tool constitutes an assembly which is to be lowered into the well bore by means of an operating pipe 2 which serves as a support for the rest of the structure. This pipe is threaded at its lower end at 4 and is arranged to receive footpiece 5 by means of this releasable thread l. A packing 6 may serve to form a seal at the lower end between the pipe and the foot piece.

A back pressure valve 1 is arranged in the foot piece and is normally retained in closed position by a spring 8 but is adapted to .open upon pressure from within the pipe 2.

Carried by the foot piece 5 is a packer assembly l0 which includes a sleeve II threaded at l2 on the outside of the foot piece. A plurality ofpacking rings l3 of compressible material are slidably mounted on the sleeve I I and held in position by a cap ring Hi. This cap ring is held against rotation relative to the sleeve by a pin I! which is slidable in a slot l8 in the sleeve. Mounted on top of the cap ring I6 is a set of slips 20 which have upwardly facing teeth 2| to engage the casing or pipe in the well in order to anchor the tool. These slips are arranged to be expanded by the movement of a mandrel 22 in the upper end thereof. The lower end of this mandrel is tapered to fit within the slips and is normally held against expanding the slips by the shear pin 24 which connects the mandrel and the sleeve.

A pair of contact shoulders 25 on the mandrel and the sleeve limit the upward movement of the mandrel relative to the sleeve.

The mandrel 22 is best seen in section in Fig. l and extends upwardly beyond the lower tapered end thereof and is provided with a set of packing 21 adjacent its upper end which packing is con- ,fined by a gland 28. Arranged for sliding moveheld in position by a gland 36 so as to provide a seal about the outside of the pipe 2, and it is intended that in the normal operation, until the tool is to be removed, that this packing will hold I the pipe 30 stationary on the pipe 2.

Inside of the mandrel 22 below the collar 2| is a plunger 31 which is anchored in the mandrel by means of a gland 38. This plunger is slidable on the periphery of the pipe 2 but is fixed to the mandrel.

The pipe 2 has port 40 ,therein above the plunger 31 which opens into the annular space inside of the mandrel and the releasing pipe 30. This port is open down to the top of the plunger 31.

Inside of the pipe 2 is an orifice or choke 43 which is fixed in position and has an opening 44 therein of a reduced size so that when any suitable flow of liquid is forced downwardly thru the pipe 2 this choke 44 will tendto force such liquid outwardly thru the port 40. The plate 43 is of a material which can be readily worn away or disintegrated after a short period of time so that after a period of circulation the inside of the pipe 2 will be opened up to permit a full flow therethru.

- An additional port or passage 45 is provided in the pipe 2 at the elevation oi! the plunger 31 as seen in Fig. 1. This opening is normally closed by the. plunger when the parts are in the position of Figs. 1 and 2 ready to be lowered into the well bore.

The inside of the releasing pipe 30 carries a plurality of spaced lugs 41 which are arranged to interfit with the spaced lugs 48 on the periphery oi the pipe 2 so that when the thread 4 is released and the pipe 2 raised upwardly the pipe 2 will be pulled. up thru the pipe 30 and the gland 36 and the lugs 48 will engage the shoulder 49 inside of the releasing pipe so that an upward pull may be exerted on the pipe 30. This upward pull from the pipe 30 is transmitted thru the collar 3| against the lower side of the packing 21 so as to in turnexert an upward pull on the mandrel 22. This upward pull on the mandrel 22 removes the lower tapered portion thereof from within the slips so that the slips are released and the resiliency of the packings I! will permit the packing to collapse so that the.

pass thru the orifice plate 43 however and gridually wear the plate away so as to open the pipe to a full flow.

If it is desirable to have washed the well prior to setting of the tool a lower pressure could have been applied which would have been insuflicient to have sheared the pin 24 and in this manner a circulation could have been downwardly thru the entire tool and upwardly around the outside thereof. When it was desired to set the slips however, the pressure would he stepped up so that the pressure on the plunger 21 would shear the pin 24. The back pressure valve I may provide the restriction to force liquid against the plunger and the choke omitted.

With the parts in this position cement would be introduced into the upper end of the pipe 2 and forced downwardly thru the pipe to open the back pressure valve I and discharge the cement into the well bore.

With this operation it is presumed that there is an outlet for the liquid in the well as the same is introduced upwardly around the outside of the casing 50. In event there was no such opening audit was necessary to introduce the cement then the cement might be pumped downwardly thru the tool at a slow rate before the setting of the slips and the packer. As the cement is discharged the tool would be gradually raised in the casing. When the desired amount of cement has been introduced in this manner then the pressure would be increased, the slips set and the packer expanded to form a seal. whereupon additional pressure could be exerted .on the cement to create the desired pressure and force it into the desired position. When this pressure is cut ofl in the pipe 2 on either manner of manipulation the pack pressure valve 1 would instantly close and drop the pressure on the cement so that y the retainer could remain in position during the period when the cement is to set..

In order to maintain a circulation in the casing 50 above the cementing tool and in order to wash applied to the pipe 2. Choke 44 will force this liquid outwardly thru the port 40 and against the upper exposed side of the gland 38. This pressure tends to move the plunger 31. and the mandrel 22 downwardly so as to force the tapered portion of the mandrel into the slips 20 and expand them against the pipe so that the parts assume the position shown in Fig. 4 when an upward pull-is exerted on the pipe 2 after the slip has been set. This tension is exerted thru the pipe 2 due to the threaded connection at 4 so that the packer I 0 -is expanded as seen in In this manner any desired pressure may be applied to the Packer due to the tension on the 7 ing 50 and upwardly thru thepipe 2 or in reverse 2 can then be raised slightly and if desired a circulation or mud, waterorother liquid can be forced downwardly inside of the casing 50 whereupon it will pass the slips and enter the openings l8. From thence it will flow into the lower end oi thepipe 2 which is now released and upwardly thru the pipe, washing out any cement which remained in the tool. By raising and lowering the tool the cement in the chamber above the plunger 31 can be washed out so that the tool may be entirely cleaned while the retainer remains in position.

In some instances it maybeidesirable'to remove the retainer at once after the cementhas been positioned, while'in other instances it may be desirable to leave the retainer in position, holding the pressure on the cement until the cement has completely set. In either event it is possible to maintain circulation downwardly thru the casthereof as occasion may desire.

leased and may reenter the pipe. Some flow will 76 When the'tool is to be removed from the well if the entire assembly is to be removed it is only necessary to raise upwardly on the pipe 2 until the lugs 48 contact the shoulder. Anvupward pull will thus tend to raise releasing sleeve 30 so that the collar 3| engages the lower end of the packing 21 and the mandrel 22 is then withdrawn from the slips'and the entire device can be pulled from the well. A jarring or knocking effect to release the packer may be obtained by raising the pipe sharply.

In some inst ces the packer may have become lodged in position due to the setting of the cement and it might be found impossible to remove it in the manner just described. If this occurs it is desirable to remove the pipe 2 from the well so that drilling operation may be resorted to in order to remove the asesmbly or a suitable fishing assembly may be lowered into the well to exert a stronger pull upon the device in order to remove it. Under these circumstances it is desirable to disconnect, the sleeve 30 from the remainder of the assembly. To accomplish this the pipe 2 is rotated and the interfitted lugs 41 and 48 impart rotation to the sleeve 30 so as to unscrew the connection 33 between the collar 3| and the pipe 30. This completely releases the pipe 30 so that it may be raised upwardly and raised from the well along with the pipe 2.

It may be desirable to leave the packer and anchor in the well and no attempt made to jar it loose or remove it. If this procedure is to be followed after the thread 4 is released and washing accomplished or whenever desired, the pipe 2 will be eased upwardly until the lugs 41 and 48 are interengaged whereupon the pipe 2 will be rotated and the thread 33 released leaving the packer anchored in the well.

Broadly the invention contemplates a removable cementing tool which can be anchored by hydraulic pressure, the pressure being retained on the cement during the setting and circulation accomplished thru the tool so that the tool may be readily removed from the well after the operation has been completed but the device is capable of use merely as a packer to be set hydraulically.

What is claimed is:

1. A removable cement retainer for wells including an operating string of pipe, a packer sleeve threaded to said pipe at its lower end, a packer on said sleeve, a set of slips on said sleeve above said packer, a hollow mandrel about said pipe to set said slips, a plunger carried by said mandrel and closing a space therein about said pipe, a port in the pipe opening into the closed space, and means in the pipe to restrict the flow of liquid therethru so as to apply pressure in the a closed area to move said plunger and mandrel to expand said slips.

2. A removable cement retainer for wells including an operating string of pipe, a packer sleeve threaded to said pipe at its lower end, a packer on said sleeve, a set of slips on said sleeve above said packer, a hollow mandrel about said pipe to set said slips. a plunger carried by said mandrel and closing a space therein about said pipe, a port in the pipe opening into the closed space, and means in the pipe to restrict the flow of liquid therethru so as to apply pressure in the closed area to move said plunger and mandrel to expand said slips, said means being constructed of a material to wear away upon circulation of liquid therethru so as to open up the pipe to full flow.

3. A removable cement retainer for wells including an operating string of pipe, a packer sleeve threaded to said pipe at its lower end, a packer on said sleeve, a set of slips on said sleeve above said packer, a hollow mandrel about said pipe to set said slips, a plunger carried by said mandrel and closing a space therein about said pipe, a port in the pipe opening into the closed space, means in the pipe to restrict the flow of liquid therethru so as to apply pressure in the closed area to move said plunger and mandrel to expand said slips, and an additional port in said pipe below said means and normally covered by said plunger, but positioned to be uncovered after movement of the plunger to set said slips whereby the flow of pressure liquid may reenter the P 1 4. A removable cement retainer for wells including an operating string of pipe, a packer sleeve threaded to said pipe at its lower end, a packer on said sleeve, a set of slips on said sleeve above said packer, a hollow ,mandrel about said pipe to set said slips, 9. plunger carried by said mandrel and closing a space therein about said pipe, a port in the pipe opening into the closed space, means in the pipe to restrict the flow of liquid therethru so as to apply pressure in the closed area to move said plunger and mandrel to expand said slips, an additional port in said pipe below said means and normally covered by said plunger, but positioned to be uncovered after movement of the plunger to set said slips whereby the flow of pressure liquid may reenter the pipe, and openings thru said sleeve whereby circulation of liquid may occur upon unscrewing of the pipe from said sleeve.

5 A removable cement retainer including an operating pipe, a packer assembly thereon, fluid pressure operable means to form an anchor in the well for the packer so that a pull exerted on said pipe expands the packer, a releasable connection between said pipe and assembly so as establish circulation in the well thru said pipe, and additional means on said pipe and said assembly to be engaged upon upward movement of said pipe so as to withdraw said first means and release said anchor and packer to remove the entire retainer from the well.

6. A removable cement retainer including an operating pipe, a packer assembly thereon, fluid pressure operable means to form an anchor in the well for the packer so that a pull exerted on said pipe expands the packer, a releasable connection between said pipe and assembly so as establish circulation in the well thru said pipe, additional means on said pipe and said assembly to be engaged upon upward movement of said pipe so as to withdraw said first means and release said anchor and packer to remove the entire retainer from the well, and an additional releasable connection in said anchor to release said pipe in event said anchor and packer remain stuck in the well.

7. A removable cement retainer including an operating pipe, a packer assembly thereon, fluid pressure operable means to form an anchor in the well for the packer so that a pull exerted on said pipe expands the packer, a releasable connection between said pipe and assembly so as to establish circulation in the well thru said pipe, additional means on said pipe and said assembly to be engaged upon upward movement of said pipe so as to withdraw said first ,means and release said anchor and packer to remove the entire retainer from the well, and an additional releasable connection including a threaded area in said anchor to release said pipe in event said anchor and packer remain stuck in the well.

8. The combination in a cement retainer of a packer assembly to beset, an operating pipe actuable for setting the packer \after the same has anchored, a choke in said pipe, means operable by fluid pressure diverted by said choke to anchor said packer, and additional means to release said packer for removal by said pipe.

9. The combination in a cement retainer of a packer assembly to be set, an operating pipe actuable for setting the packer after the same has anchored, a choke in said pipe, means operable by fluid pressure diverted by said choke to anchor said packer, and additional means to release said packer for removal by said pipe including a jar to knock said packer loose.

10. A tool of the character described including an operating pipe, a packer assembly thereon, fluid pressure operable means to form an anchor in the well for the packer so that a pull exerted on said pipe expands the packer, a releasable connection between said pipe and assembly, additional means on said pipe and said assembly to be engaged upon upward movement of said pipe so as to withdraw said first means and release said anchor and packer to remove the entire retainer from the well, and an additional releasable connection including a threaded area in said anchor to release said pipe in event said anchor and packer are to be left in the well.

11. A packer assembly for wells including an operating string of pipe, a packer sleeve threaded to said pipe at its lower end, a packer on said sleeve, a set of slips on said sleeve above said packer, a hollow mandrel about said pipe to set said slips, a plunger carried by said mandrel and closing the space in the mandrel about said pipe, a port in the pipe opening into the closed space,

pand said slips.

GEORGE GREEN. 

